Experiments and observations on the vegetation of plants : which shew that the common opinion of the amelioration of the atmosphere by vegetation in solar light, is ill founded / by James Woodhouse.

  • Woodhouse, James, 1770-1809.
Date:
[1802?]
Catalogue details

Licence: Public Domain Mark

Credit: Experiments and observations on the vegetation of plants : which shew that the common opinion of the amelioration of the atmosphere by vegetation in solar light, is ill founded / by James Woodhouse. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    THE air of the atmosphere, according to the most celebrated chemists, is composed of twenty-two parts of oxigenous gas or air, and seventy-eight parts of azotic gas. There is a constant con- sumption of the oxigenous portion of this air, by the burning of combustible bodies ; by the respiration of animals ; by the fermen- tation and putrefaction of vegetable and animal substances ; and by the calcination of metals. The oxigenous gas, decomposed by res- piration and combustion only, in the city of London, is supposed to amount to the enormous quantity, of five millions cubic feet an hour. (Nicholson's Philosophical Journal.) The atmospheric air of Great Britain, France, of parts of Africa, and of America, has been examined by philosophers, and has been found to be exactly of the same degree of purity. The oxigenous gas contained in it, is in the same proportion, at all times and in all places, in rainy or in dry weather, in the depth of winter, and in the middle of summer, on the land and on the ocean, in the crowded city and remote village. In consequence of a most valuable discovery, made by the illus- trious Dr. Prikstlky, that growing vegetables under certain circumstances, exposed to the light of the sun, yield oxigenous gas ; an opinion has been adopted, that they are the sources of the oxige- nous part of common air.* This sentiment has been adopted by the chemists of all nations, but has lately been controverted by Dr. James Woodhouse, pro- fessor of chemistry in the University of Pennsylvania. (Nichol- son's Philosojihical Journal.) The Doctor reasons in the following manner : 1st. He says, whenever oxigenous gas has been obtained from vegetables, carbonic acid, or fixed air, has been present. Upon reviewing the experiments of Dr. Priestley, he finds that this circumstance has actually taken place. The Dr. exposed plants to the influence of light, in atmospheric air, in which spirit of wine, and wax, and tallow candles, had burned out ; to air which had been vitiated by the death or putrefaction of mice and fishes ; and to air which had been frequently taken into his lungs, and that the purity of the air, was in every instance restored. (Pkil.t- t.ey on air. Vol. iii. p. 247 to 349.)